Labels are applied to fruit and vegetables in packing houses, where the speed at which the labels are applied, the accuracy of the label application, and the space required by the labeler, i.e. the labeler footprint, are important. Speed is important because the fruit must be packed and shipped quickly so that the shelf life in stores will be as long as possible and the speed of the labeler may be the limiting constraint. This constraint of labeler speed may also result in inefficient use of other equipment and personnel in the packing house, thus increasing the overall cost of operation.
Accuracy, in the form of the successful application of the proper label to the fruit, is important because packing house profitability is adversely affected when a label that would have permitted a higher selling price is not applied to fruit otherwise capable of commanding such a higher price. Space is also important because of the physical configuration of any given packing house. The fruit is transported in a series of lanes, each lane conveying fruit on a plurality of cradles connected to an endless belt, each cradle supporting and locating an individual fruit. The fruit in each lane is sized by conventional sizing means and subsequently conveyed past a plurality of labelers arranged in series or banks, each of the labelers in the series of labelers being loaded with a different label, i.e. a label imprinted with indicia to identify the size of the fruit. The physical arrangement of the packing house often limits, without major reconstruction of the building, the number of banks of labelers it is possible to install.
U.S. Pat. No. 4,547,252 to LaMers discloses a labeling apparatus, such as for fruit, and including an extendable bellows for placing the labels. The bellows is moved past a magazine or cassette which dispenses the labels from a carrier strip. The labels are held in position on the distal end of the bellows by application of a vacuum to the bellows, which also serves to maintain the bellows in a retracted position. As the bellows is moved to an application position adjacent a fruit, positive pressure is applied and the bellows is extended to contact the fruit and apply the label thereto.
As also disclosed in the patent, a tricuspid check valve is integrally formed on the distal end of the bellows. The valve admits air from outside the bellows to the interior of the bellows, but prevents the flow of air out of the bellows. Accordingly, in theory, the label may be held in position by the vacuum applied to maintain the bellows in the retracted position. When the bellows is extended by positive air pressure, the valve in theory is closed to prevent blowing the label off of the end of the bellows and thereby missing the fruit.
Unfortunately, the integrally formed valve may become gummed with adhesive from the adhesive labels or from wax carried by the fruit. If the valve becomes stuck open, when positive pressure is applied, the label may be ejected prematurely. If the valve becomes gummed in a closed position, the bellows may not pick up the labels and the dispensing cassette may jam thereby requiring maintenance.
Published European patent application 113,256 assigned to Sinclair discloses a labeler including a plurality of extendable bellows rotated between label pick-up and label applying positions. In a related commercial embodiment of the Sinclair labeler, a flexible diaphragm has been used in place of the tricuspid check valve. The flexible diaphragm is secured to the inside distal end of the bellows. When a vacuum is applied, the diaphragm opens to expose a series of openings in the distal end. Accordingly, the label is held in position by vacuum communicated to the end openings. When positive pressure is applied to extend the bellows, the flexible diaphragm desirably seals against the openings.
Unfortunately, the diaphragm arrangement may be subject to the same shortcomings as the tricuspid check valve. In other words, the accumulation of adhesive and/or wax could stick the diaphragm in either the opened or closed positions. Accordingly, fruit may not be properly labeled, and additional maintenance may be required for the labeler.